Automatic die-casting apparatus



Nov. 20, 1934. K. F WAGNER 1,981,380

- AUTOMATIC'DIE CASTING APPARATUS Filed Aug. 25, 1931' 2 Sheets-Sheet 1 6 mm: A i Z2 a 0 0 WWW @WW 91 mi 4 B INVENTOR- KaAZ FHeMocZ Wn fwr TTORNEYS Nov. 20, 1934. K. F. WAGNER 1,981,380

AUTOMATIC DIE CASTING APPARATUS I Filed Aug. 25, 1931 '2 Sheets-Sheet 2 MFMM W new 5 yp-w drm /47-r0 ENEYS Patented Nov. 20, 1934 I UNITED STATES PATENT OFFICE AUTOMATIC DIE-CASTING APPARATUS Karl Friedrich Wagner, Stuttgart, Germany, as-

slguor, by mesne assignments, to Magnesium Development Corporation, Newark, N. .L, a corporation of Delaware Application August 25, 1931, Serial No. 559,249 In Germany August 28, 1930 10 Claims. (01. 22-69) This invention relates to a method of and positive manner, when the conditions necessary means for assuring the safe working of autofor the safe continuance of operation are absent matic pressure die-casting apparatus. and particularly, when the stage of operation to In connection with the mechanical production be safeguarded has not been correctly and comof pressure die-castings, the need arose, at an pletely performed. The stopping of the appaearly period, 'for safety measures to prevent the ratus is preferably effected by providing between unintentional performance of individual working the working stages concerned, a separate safety stages, 01'' their performance in incorrect serial stage which is also actuated by the control order. The desire for such measures has led to mechanism of the apparatus and stops the same numerous proposals, most of which naturally when necessary.

65 relate to the safe operation of manual appa- A preferred method of achieving this result ratus and only a few to automatic pressure dieconsists in providing a safety stage in the form casting apparatus. of a reciprocatory pawl which, when the condi- In contradistinction to the foregoing, the tions assuring safety are lacking, engages a lever present invention relates to a method of and which throws out the clutch of the control means for assuring the safe working of automechanism, said pawl however being drawn-in matic pressure die-casting apparatus, especially when the conditions are normal, so that it cannot those with. hydraulic control, and in which most actuate the lever. of the operations, and particularly the closing In order to more clearly understand the nature and Opening of the Parts Of the mold, and a so of the present invention, reference is made to 75 the start a d st ppin of t e i ect p the accompanying drawings, which illustrate diasure, are actuated or initiated in a definite serial grammatically and by way of example, two emorder and at definite inte a s, for example y a bodiments of apparatus suitable for carrying out single or several rotating cam shafts. The theinvention, and in which arrangements of the present invention differ Fig. 1 afiords a view of the device (A) which 80 fundam nta ly m h s pr vi usly su st d, stops the apparatus, and also of the members in that t p l of p v tin a succ din (B1, B2 and c) actuating said device. working stage from being initiated until the Fig. 2 showsaspecial improved embodiment of preceding stage has been correctly performed, the device for stopping the machine when occaor quite completed, is propounded and solved for sion requires. 8

the first time herein. With reference to Fig. l a is one of a series of Safety measures of this kind e chiefly needed valves which control the respective stages of opto prevent: eration of the machine, said series of valves being (1) The injectio p ssur being ed on arranged in a block so as to form a pressure diswhen the halves of the mold re not completely tribution system. The valves are operated in a 90 closed, 01' u t a tight Connection has been suitable manner, as shown in connection with established between the mold and the injection 'valve a, through the medium of tappets b and nozzl I i p rly ess nti l tha th inrollers c rotatably mounted at the ends of the J t pr s u s u not come into action tappets and in contact with cams d mounted on 40 befor th s a in pr u requisite for closing the cam-shaft e. According to the invention six 9 a d lock t halves of the mold, nd the invalves are provided in the pressuredistribution jection nozzle connection with the mold has been system for actuating the various safety stages, attained, since otherwise the admission of the said valves being arranged in pairs, and each pair injection pressure would force the fluid metal serving to actuate a safety pawl by means of conthrough any openings between the mold halves trolling the hydraulic pressure acting on the 100 between the injection nozzle and them ld; pistons Z1, Z2 and 13, to the rods of which the pawls (2) The detachment of the mold from the 1'1, 1'2 and is are attached. injection nozzle, so long as any positive pressure The pairs of cams serving to actuate the restill exists in the pressure chamber opening into spective safety pawls are so designed and po i the injection nozzle, since otherwise, the fluid tioned on the cam shaft e that on completion of 105 metal would be projected through the nozzle into each of the working stages to be safeguarded, the atmosphere. for example, closing the mold and positioning it .According to the present invention these reover the injection nozzle, establishing the necesquirements are taken into consideration in that sary hydraulic locking pressure for the mom the operation of the apparatus is stopped in a halves, and rehevmg the mJGCtlOn pressure in the pressure chamber, the proper pair of valves is actuated.-

The pawls i1, i2 and is are normally held in engagement with a suitable clutch lever g by means of tension .springs k. The clutch lever g is constructed in the form of a bell crank, one arm of which is forked, and as shown in Fig. 1, the bell crank is pivotally mounted in such a manner that its forked arm engages the dog clutch ,f, of any suitable conventional design, while the arm, which is actuated by the pawls when required, is normally held, by means of a counter spring 71., to keep the clutch engaged.

The mechanism 131 which sets the safety device in operation is actuated when the parts of the mold are closed and the mold is firmly seated, as a unit, on the injection nozzle. For this purpose, there is provided an intermediate member m, positioned on the mould 0 which, in turn, rests on the press table n containing the injection nozzle, not shown. A striker pin p, rigidly secured to the member m, provides for actuating a single lever q which is attached by means of a rod or the like to the pawl i1, whereby the pawl is drawn downwardly only when the mold is com- 'pletely closed.

cylinder communicates with the high-pressure stage of the locking cylinder of the machine, so that the hydraulic pressure applied for tightening up the mold, in each case, acts on this side of the piston. When the locking pressure has been attained, the piston compresses the spring and thus draws the pawl i: by means of a suitable tractive member.

The mechanism C which prevents the mold a from being removed from the press table carry,-

ing the nozzle or nozzles, not shown, before the injection pressure in the pressure chamber has been completely relieved, is built into the vent pipe which opens into the delivery side of the pressure chamber and is evacuated by a valve in the usual manner. In the neutral position, the piston t is retained by a spring u, in a position in which it closes the vents w. On the pressurerelief valve, not shown, being opened, the compressed air overcomes the slight force of the spring and drives the piston far enough to enable said air to escape through the vents to. At the same time, the piston actuates the lever 12 and by so doing, (enables the pawl is to be drawn downwardly by means of a suitable tractive member, thus allowing the mold to be removed from the press table.

The arrangement operates in the following manner: I

So long as the mechanisms B1, .132 or C operate to pull downwardly on the-corresponding pawls, the reciprocating movements of the pistons l1 l: or 13 cannot actuate the clutch lever so as to disengage the clutch inasmuch as the pawls slide freely under the lever.

However, when any one of the members B1, B2 or C remains inactive, that is to say, when the conditions for the'safe continuance of the work ing operations of the apparatus are not fulfilled,

lease the corresponding pawls only during the period in which the safety device connected with the corresponding pawl engages the lever g during the reciprocating movement of the corresponding piston Z, thus causing the lever to open the clutch and automatically stop the machine.

The embodiment of the stop mechanism (A) shown in Fig. 2 represents an improvement over that described above, inasmuch as only a single piston l, and a pair of valves a in the distributor are needed for actuating the throw-off lever g. The valve pair is actuatedby two cams di and d2 in each case, and thus reciprooates the piston l. The forked end of the piston carries the pawls -i1, i2, and is, which in turn, act on the long arm of the lever g, in the manner already described. However, since each of the safety devices B1, B2 and C can only be actuated during the corresponding working stage, means must be provided to prevent the lever g from being engaged, during the reciprocating movement of the piston, by the pawls which are inactive during such stage. This is accomplished by means of the cams x1, x2 and x3, which are also mounted on the am-shaft e and act directly on the several pawls, he cams being of such contour that in each case, they remeans of an automatically driven control mechanism, comprising means for disengaging said control mechanism from its driving means, and means for causing said disengaging means to act at the termination of any one ofthe working stages on failure of such working stage to complete its function.

2. A safety device for controlling automatic die-casting apparatus in which a plurality of working stages are performed in definite sequence, comprising a pressure distribution system clutchconnected to a driving means, an element associated with each working stage of the pressure distribution system, said elements being adapted to disengage the clutch on failure of any one of the working stagesto complete its function. g

3. A safety device for controlling automatic diecasting apparatus in which a pluralitS of working stages are performed in definite sequence,

comprising a pressuredistribution system clutchconnected to a driving means, a plurality of pawls equal in number to the number of working stages, said pawls being actuated by the pressure distribution system and adapted to disengage the clutch between the driving means and the pressure distribution system upon failure of any one of the working stages to complete its function.

4. A safety device for automatic pressure diecasting apparatus in which a plurality of workof any one of the working stages to complete its 150 function, and said connecting elements preventing engagement of the clutch lever by said pawls so long as the working stages complete their functions.

5. A safety mechanism for automatic pressure die-casting apparatus in which the working stages, closing the mold and seating the same upon an injection nozzle, locking the mold and establishing a tight connection between the mold and the injection nozzle, and relieving the pressure for injecting molten metal through the injection nozzle into the mold, are performed in the order named; said safety mechanism comprising means associated with elements of the die-casting apparatus for performing the abovementioned working stages, said associated means being connected with safety pawls for safeguarding the performance of the working stages in definite sequence, a cam shaft for actuating the safety pawls across a clutch lever controlling the operation of said cam shaft, means connecting said pawls with said elements of the die-casting machine for performing the working stages, said connecting means being adapted to withdraw the safety pawls out of engagement with said clutch lever when the working stages are correctly performed, said pawls being adapted to disengage said clutch lever and interrupt the operation ,of the die-casting apparatus on failure of any one of the above-mentioned working stages to perform its function.

6. A safety mechanism for controlling the working stages of a pressure-operated die-casting apparatus in which the working stages, closing and seating a mold upon an injection nozzle, locking the mold and establishing a tight connection between the mold and the injection nozzle, and relieving the pressure for injecting molten metal into the mold, are performed in the order named; said safety mechanism comprising devices associated with those portions of the diecasting apparatus which are employed in the direct performance of the above-mentioned working stages, a series of cams operating in timed relationship with respect to the working stages, said cams being adapted to control through valves the reciprocation of a series of safety pawls equal in number .to the number of working stages, an oscillatory clutch lever adapted to disengage the cams from a driving means, said clutch lever being normally resiliently pressed into operative engagement, said safety pawls being adapted to engage said clutch lever to disengage the cams from the driving means on failure of any one and all of the working stages. I

'7. A safety mechanism for controlling the working stages of a pressure-operated die-casting apparatus in which the working stages, closing and seating a mold upon an injection nozzle, locking the mold and establishing a tight connection between the mold and the injection nozzle, and relieving the pressure for injecting molten metal into the mold, are performed in the order named; said safety mechanism comprising a pressure distribution system having a series of valves arranged in' a housing, a cam shaft associated with said valves and adapted to actuate the same in timed relationship with respect to the working stages, a clutch connecting said cam shaft to a driving means actuating said automatic diecasting apparatus, a clutch-manipulating lever associated with said clutch, a series of cylinders and pistons in combination with said pressure distribution system, said pistons being adapted to are held out of engagement with the clutch lever so long as all of the working stages are properly performed.

8. A safety device adapted to control the sequence of operations in an automatic die-casting apparatus having a mold, an injection nozzle, means for effecting a tight connection between said mold and said injection nozzle, pressure means for injecting molten metal into said mold through said injection nozzle, means for relieving the pressure in said pressure means when said mold is filled, means for disconnecting the said injection nozzle from said mold, and driving means for operating the aforesaid means in sequence; said safety device comprising a clutch mechanism for connecting said driving means to a power shaft, a reciprocatory member adapted to disengage said clutch, and means for operating said reciprocatory member upon the failure of any of the aforesaid means to complete its function.

9. A safety device adapted to control the sequence of operations in an automatic die-casting apparatus having a mold, an injection nozzle, means for effecting a tight connection between said mold and said injection nozzle, pressure means for injecting molten metal into said mold through said injection nozzle, means for relieving the pressure in said pressure means when said mold is filled, means for disconnecting the said injection nozzle from said mold, and driving means for operating the aforesaid means in sequence; said safety device comprising a clutch mechanism for connecting said driving means to a power shaft, said clutch mechanism comprising a bell crank lever one arm of which is adapted to open and close said clutch, and the other arm adapted to actuate the first-mentioned arm, safety pawls adapted to engage said actuating arm, said pawls being connected to a piston for reciprocatory motion, a cylinder enclosing said piston, a valve and valve housing in association therewith, said valve being actuated by the drive shaft whereby pressure is admitted to said cylinder to-reciprocate said safety pawls, and means mounted on said drive shaft in contact with said safety pawls to hold them out of engagement with said actuating arm, whereby the clutch may be held in engagement.

10. A safety device for controlling automatic die-casting apparatus in which a plurality of working stages are performed in definite sequence, comprising a plurality of safety pawls mounted for reciprocatory movement, pressure-operated means for reciprocating said pawls, said pressureoperated means being actuated through a clutch by the die-casting machine driving means, a clutch lever associated with said clutch, said pawls being adapted to engage said clutch to disengage the pressure-operated means from the die-casting machine driving means, and means associated with the pawls and driving means for holding the pawls out of engagement with said clutch lever.

KARL FRIEDRICH WAGNER. 

